It's actually super strait forward. Here's some of the stuff copied from our internal wiki (stolen from various sources, sorry if I am not crediting people). It works with defaults but here is stuff you can look at. There is also a locking issue if you use VMware snapshots but we don't.
Netapp Specific:
When a cluster failover occurs on a NetApp FAS storage system, NFS
datastores within VMware ESX v3.x may go offline, requiring an
administrator to re-create the NFS datastores and connect them to the
FlexVols presented from the FAS storage system.
Cause of this problem The NFS client in VMware ESX v3.x has
several default settings, which relate to how long the effective
timeout period is for NFS volumes.
The default settings may not account for the length of time required
for a FAS system to perform a cluster failover. Solution
Using VMware Virtual Center, repeat this for each ESX server in the HA datacenter using NFS datastores:
1. Select the ESX server. Select the configuration tab. Select advanced settings. Select NFS.
2. There are 3 settings that need to be changed:
NFS.HeartbeatFrequency NFS.HeartbeatTimeout
NFS.HeartbeatMaxFailures The NFS client relies on Heartbeats to verify
the NFS volume is available. Increasing the NFS Heartbeat frequency
will ensure that datastore IO can resume much sooner once the cluster
failover has completed.
When considering the overall timeout period, it is necessary to understand how these 3 settings interact.
A simple formula that can be used is (X x Z) + Y = effective timeout period in seconds
Where:
X=NFS.HeartbeatFrequency
Y=NFS.HeartbeatTimeout
Z=NFS.HeartbeatMaxFailures
For example, in ESX v3.0.2, the default values are:
NFS.HeartbeatFrequency = 9
NFS.HeartbeatTimeout = 5
NFS.HeartbeatMaxFailures = 3
With NFS.HeartbeatFrequency set to 9, then a heartbeat will occur every 9 seconds.
Each heartbeat will wait for 5 seconds (the value of NFS.HeartbeatTimeout ) before timing out.
Every time a heartbeat time out occurs, the heartbeat failures count is increased.
Once the heartbeat failures count is equal to the value set with
NFS.HeartbeatMaxFailures, the datastore is marked as failed and taken
offline.
So the default settings in ESX v3.0.2 result in a heartbeat every 9 seconds. Each heartbeat has 5 seconds to succeed.
This means that the first heartbeat will begin at 9 seconds, and
fail at 14 seconds. The second hearbeat will begin at 18 seconds, and
fail at 23 seconds. The third heartbeat will begin at 27 seconds, and
fail at 32 seconds. At this point the max failures count will equal 3,
which is the value of NFS.HeartbeatMaxFailures
At this point, because the MaxFailures threshold has been
reached, the datastore is taken offline 32 seconds after the NetApp
cluster failover began.
Usually, a NetApp cluster failover operation will not complete
within 32 seconds, so to ensure NFS datastores can withstand NetApp
cluster failover operations, we can use the following settings:
NFS.HeartbeatFrequency = 12
NFS.HeartbeatTimeout = 5
NFS.HeartbeatMaxFailures = 10
This will provide an effective timeout period of 125 seconds (12 x 10) + 5 = 125 seconds.
If the NetApp cluster failover begins at 0 seconds, then the
first heartbeat will occur at 12 seconds. The first heartbeat will fail
at 17 seconds. The second heartbeat will begin at 24 seconds, and will
fail at 29 seconds. The third heartbeat will begin at 36 seconds and
fail at 41 seconds. *This will continue until the 10th heartbeat,
which will begin at 120 seconds, and fail at 125 seconds – although the
NetApp cluster failover should have completed by this time, so the 9th
or 10th heartbeat should not timeout.*
<span class="mw-headline">Opening the firewall for NFS client traffic
<span class="editsection">[[edit|http://gsovmwiki01/mediawiki/index.php?title=Configuring_NFS_storage&action=edit§ion=2|Edit section: Adding the NFS stores]] <span class="mw-headline"> Adding the NFS stores
On a fresh install you may not see anything or you'll see the
internal disks on your ESX host. If you are connected to a Fibre
Channel network (being phased out in GSO) you may see the FC LUNs if
you are using HBA's that have previously been configured for this
network (we use soft zoning).
In the VI client go to your ESX host and select the Configuration tab, then select Networking.
Create an empty switch (No port groups),add your NICs to them.
ssh into the ESX server
esxcfg-vswitch -m 7500 vSwitchX (sets the vSwitch MTU)
esxcfg-vswitch -A NFS vSwitchX (adds a portgroup to the switch named NFS)
esxcfg-vmknic -a -i 172.1.2.X -n 255.255.0.0 -m 7500 NFS (sets the portgroups information)
esxcfg-vswitch -l (verifies that setup was correct)
Make sure the switch is set to IP Hash for load balancing
<span class="editsection">[[edit|http://gsovmwiki01/mediawiki/index.php?title=Configuring_NFS_storage&action=edit§ion=3|Edit section: Verifying NFS access]] <span class="mw-headline"> Verifying NFS access
Go to the Summary page on the ESX host
Select the NFS storage group in the Datastore window and double click it
Right click and create a new folder
If it succeeds your server has the rights it needs to run a VM off that NFS mount, please delete the folder
<span class="editsection">[[edit|http://gsovmwiki01/mediawiki/index.php?title=Configuring_NFS_storage&action=edit§ion=4|Edit section: Tuning NFS]] <span class="mw-headline"> Tuning NFS
Open VirtualCenter.
Select an ESX host.
In the right pane, select the Configuration tab.
In the Software box, select Advanced Configuration.
In the pop-up window, select NFS in the left pane.
Change the value of NFS.MaxVolumes to 32. See Figure 4.
In the pop-up window, select Net in the left pane.
Change the value of Net.TcpIpHeapSize to 30.
Repeat for each ESX server
<span class="editsection">[[edit|http://gsovmwiki01/mediawiki/index.php?title=Configuring_NFS_storage&action=edit§ion=5|Edit section: Troubleshooting NFS problems]] <span class="mw-headline"> Troubleshooting NFS problems
Make sure you enabled load balancing on the NFS vSwitch
ssh into the ESX server. See if you can vmkping the target
See if you can vmkping -s 7500 the target (uses a jumbo frame)
See if you can navigate to /vmfs/volumes and change into the NFS directory
On the filer run vol options <vol-name> no_atime_update on
This will disable last access time stamps when accessing files via NFS.
